Lawn Mower won’t start , starter cable pulls back / snaps back out of hand. 4 possible solutions

This video won’t show you HOW to do the work, it simply helps diagnose. Below are links to videos that show how to do the first 3 things I mention.
My Briggs and Stratton engine was ripping the pull cable right out of my hand, which is startling and painful when it happens. I found 3 solutions mentioned in the following videos. But mine ended up being a fourth problem, which if you want to jump ahead to that one, go to the 5:00 mark.
Valve adjustment
• Free Craftsman Pull Co...
Fixes
• Mower Pull Cord Snaps ...
Sheared flywheel key
• Recoil Kickback on Cra...
• Mower Cord Pulls Back ...